Improvement in saw-mills



eti opac J. R. HOFFMAN, OF FOR'T WAYNE .lNDI'NfL Letters Pfl-tent No. 92,191, dated July 6, 1869.

IMPROVEMENT IN SAW-MILLS.

The Schedule referred to in these Letters Patent and making parte o! thel same.

To whom it may concern v Be it known that I, J. R. HOFFMAN, of Fort Wayne, in the county of Allen, inthe State of Indiana,'have invented a new and useful Improvement in Saw-Mills; and I do hereby declare that the following is a full and exact description thereof, reference being had to the accompanying drawings, and the letters ot' reference marked thereon.

My invention relatesl to that kind of saw-mill where a band or belt-saw is used for sawing lumber, by passing the band-saw around two pulleys at the proper distance apart; and y It consists in the means used for guiding, or giving direction to that portion of the saw that is operating to saw the wood, and in the devices used for adjusting the upper pulley to give the saw the necessary position on the pulleys.

To enable others skilled in the art to make and use my invention, l will describe its construction and operation.

Figure l is a view of the rear elevation of the frame;

Figure 2 is a view at right angles ot" the same;

Figure 3 is a plan view of the adjustable saw-guide and its supports; and

Figure 4 is a sectional view of the same.

A, in the drawings, represents the frame which supports the operating-parts.

A', A", and A' are cross-beams for supporting the parts ofthe machine.

B is the main driving-shaft, and upon which is sawpulley (l.

1S is the shaft upon which pulley C is hung.

D is a belt-saw, which passes aroundthe pulleys C U.

Shaft B', that carries saw-pulley C', is supported in an adjustable frame, c, and hears upon a box next the pulley-wheel C', on its under side, while the back end otl the shaft is contained in a sliding support or box, a', upon a horizontal adjustable block, a.

Upon the sliding support a', and over the shaft B', and sliding on its upper end, is a keeper, b, which is a bearing for the rear end ot' said shaft B', when there is strain upon the saw D, which causes the shaft, at its rear end, to bear on its upper side, and against the keeper or sliding box, b.

lhe sliding support c is adjustable, and slides up or down in gains out in cross-beam A and adjustable block a, and is adjusted to strain the saw D, by means of the wedge c sliding upon support A", and underneath the sliding support c, as is fully shown in gs. 1 and 2. j

Block a is adjusted horizontally, by means of holding-screws y g', working in slots g g.

The object ot' this arrangement and construction of devices is to guide the saw to be properly carried upon the pulleys O and C.'

Through that part of' support O .which is designated a', andthe keeper or box b, Tces a mortise,lin such manner, that as the key b' is forced in, it raises the sliding box b upon its support a', which will a'ect the I perpendicular position ot'wheel C', and thus change the position of the saw upon the pulleys C and O', so that the front line of the saw-teeth can be made to project, it' necessary, in front of the pulleys, or at any position desired upon the pulleys.

. Heretotore, a great difficulty has been experienced in giving the propel' direction to that part of the saw which is doing the work in the wood, and to maintain the proper position, and have the saw cut through large timber without variation, and in sawingcurved lumber, it is necessary to sometimesV change the direction thatjthe saw shall have between the pulleys.

To produce results never before attained inthe use of band-saws, and to overcome the diliiculties above enumerated, l have constructed asaw-guide, so that, through its iulluence, the saw-plate canv be changed in its direction without changing the )ight line at the points of the teeth, and only the back of the saw is moved at the right or the left to a greater or less ex tent, as may he desired.

The saw-guide E', that I have constructed, rests l upon a support, E, bearing upon and firmly attached vto support A', or to other convenient means-of tirln support.

ThisV guide E is of metal, or other materialv that will answer the purpose, and' is constructed with a circular slot, f', in the supporting-plate, `and has a holding-screw, j, in said slot.

From the under side of the base-plate is a circular projection, e, in dotted lines, as seenin dotted lines in nu. 3.

EAbove the plate is another projection, and in bpth the circular and upper projection isa slot ot' the width to receive the thickness of the saw-plate, with the front edge of the upper projection just over the centre of the circular projection on the lower side of' thev guide-plate, which front ot the upper projection should be the point at which the points of the teeth of the saw should be made to correspond whenever thel guide is used to change the saw; then, by giving the plate at the rear of the saw, a change, either one way or the other, the slot e', in the guide, will not change the line ot' the saw at the points ot' the teeth, because there is no motion at that point, butwill change the back of the saw, by forcing it, by means of the slot in the guide, to go either way, as may be desired, and thus change the direction of the saw-plate more or less at will, whenthe holding-screw is turned down and clamps the guide in its position. v The pulley-wheels O and C' are covered with India rubber ot' sullcient thickness to preventthe set in the saw-teeth being destroyed.

With this construction and arrangement, Iam ena,-

bled to adjust the saw to work easily upon the pulleys, Without the'use of Vguides at the back or sides, and thus lessen the friction, sind give more power to the saw for cut-ting the wood.

I am aware that many devices havel been used for adjusting the saw to run upon the pulleys, und to `uive direction to the sow, but none of them have the devices that I have described as new and of my invention. y

Having thus described my invention,

\Vhat I claim, and desire to secure by Letters Pat# eut, is-

1. Thecombiuation of the allait-support c with the adjusting-block w', slots g', and screw g, constructed and arranged io opera-te in the manner and for the purpose substantially ns described.

e 2. The combination of the shaft-support c wit-h the sliding keeper or box b, und adjusting-key b', all constructed and arranged to operate iu the muuuer und for the purposes substantially as described.

3. The, guide E', constructed in the manner and for the purpose described.

J.- R. HOFFMAN.

Witnesses:

A. H. BITTINGER, J. R. BITTIXGER. 

